Modern communication networks can be designed according to a hierarchical structure, wherein there are many-to-one relationships, e.g. between access nodes (base stations) and a serving gateway, and a one-to-one relationship, e.g. between the serving gateway and a data packet gateway, towards an external IP network.
A mobility management functionality of the communication network can be responsible to ensure that a mobile device attached to the communication network can be reached, for example, to notify the mobile device about incoming data packets or calls. The total area covered by the communication network can be subdivided into tracking areas (TAs). When there is no data packet to be sent or to be received, the mobile device can be in idle mode in order to save energy and network resources. In idle mode, the communication network may no longer entail the mobile device to inform the communication network every time the mobile device moves from one base station to another base station within a TA, and the mobile device can be in an energy saving state.
In order to search for the idle mobile device and to establish a communication link, a paging procedure can be applied. Paging messages can be broadcasted periodically on a common paging channel for this purpose. A paging message can e.g. comprise a number of the tracking area (TA) and identifications of mobile devices that are, or may be, in the tracking area (TA). The paging procedure can be triggered, for example, by downlink data packets arriving at the serving gateway from the data packet gateway. The mobile device may wake up to receive the paging message. Consequently, the communication link can be established and the data packet can be delivered to the mobile device.
In densely structured communication networks, however, this approach may lead to a reduced efficiency due to a large signaling overhead throughout the communication network.